Effects of Post-Exposure Naps on Change in Autonomic Arousal to a Social Challenge Across

67 Pages·2017·0.79 MB·English

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Effects of Post-Exposure Naps on Change in
Autonomic Arousal to a Social Challenge Across
Exposure Therapy for Social Anxiety
Citation
Kim, Se Yun. 2017. Effects of Post-Exposure Naps on Change in Autonomic Arousal to a Social
Challenge Across Exposure Therapy for Social Anxiety. Master's thesis, Harvard Extension
School.
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http://nrs.harvard.edu/urn-3:HUL.InstRepos:33826278
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Effects of Post-exposure Naps on Change in Autonomic Arousal to a Social Challenge
Across Exposure Therapy for Social Anxiety

Se Yun Kim

A Thesis in the Field of Psychology
for the Degree of Master of Liberal Arts in Extension Studies

Harvard University
May 2017
Copyright 2017 Se Yun Kim
Abstract

Sleep promotes memory consolidation and regulates emotion. Sleep may
strengthen therapeutic extinction learned during exposure therapy. We investigated
effects of post-exposure naps on pre- to post-treatment changes in autonomic arousal
during an experimental social stressor in people with Social Anxiety Disorder. Twenty-
six participants aged 18-39 (16 females) with mean Liebowitz Social Anxiety Scale
scores of 85 (96% > 60) completed a five-session group exposure therapy for social
anxiety. A modified Tier Social Stress Test (mpTSST) was conducted before and after
treatment. Heart rate (HR) and skin conductance level (SCL) were measured during the
baseline, performance (speech and mental math), and recovery periods of the mpTSST.
Heart rate variability (HRV) measures using time domain and frequency domain analysis
with ratio of low- to high-frequency HR oscillations (sympathovagal balance) were
computed. The third and fourth therapy sessions concluded with a speech exposure
followed by either a 120-minute nap opportunity (nap, 14Ss) or a non-arousing video
(wake, 11Ss). The nap group showed greater pre- to post-treatment decrease in SCL
during and while recovering from the social stressor, F(1, 23) = 4.54, p < .05. The post-
compared to pre-treatment SCL during mpTSST decreased in the nap group (p < .05) but
not the wake group. There was a trend toward decrease in standard deviation of all
successive R-to-R intervals (SDNN) across treatment, F(1, 21) = 4.67, p < .05, but no
group differences. Although the pre-to-post treatment main effect for sympathovagal
balance was not significant, a near trend was seen for the Time x Group interaction, F(1,
21) = 2.57, p = .12, with sympathovagal balance decreasing in the nap group—the same
pattern that was seen for the other sympathetic activity index, SCL. Thus, therapy with
post-exposure naps was associated with greater reduction in sympathetic activation to a
social stressor from pre-to post treatment. Sleep augmentation of exposure therapy may
benefit the treatment of Social Anxiety Disorder.
Dedication

I dedicate this thesis and give special thanks to my parents Dr. YJ Kim and HJ
Jang for their unconditional love and support throughout the entire process. I appreciate
their sacrifice as parents throughout these years and how they have helped me to achieve
my highest potential. I also dedicate this thesis to my sister, MJ Kim, for encouraging me
to believe in myself.

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Acknowledgments

I would like to express my gratefulness and appreciation to Dr. Edward Pace-
Schott for providing me with the opportunity to conduct this research. His dynamic
guidance, support, understanding, and patience throughout the entire process enabled me
to finish this study successfully. I would also like to thank Dr. Dante Spetter, my research
advisor, for her help and advice in this project. I would like to thank my friends and
Chuck Houston for the endless encouragement and emotional support throughout the
process and the program.

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Table of Contents

Dedication ............................................................................................................................v
Acknowledgments.............................................................................................................. vi
List of Tables .......................................................................................................................x
List of Figures .................................................................................................................... xi
I. Introduction .......................................................................................................................1
Effects of Sleep on Memory ....................................................................................2
Effects of REM Sleep on Extinction in Rats ...........................................................3
Effects of REM Sleep on Extinction in Humans .....................................................4
Effects of Sleep After Different Types of Exposure Therapy .................................6
Study Aim & Hypothesis .........................................................................................8
Significance of Study ...............................................................................................8
II. Method ...........................................................................................................................11
Participants .............................................................................................................11
Procedure ...............................................................................................................13
Schedule of Visits ......................................................................................13
mpTSST Procedures ..................................................................................14
Exposure Therapy Procedures ...................................................................16
Sleep Lab Procedures .................................................................................17
Measurements ........................................................................................................18
Psychophysiological Assessments .............................................................18
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Questionnaires............................................................................................19
Dependent Variables and Analyses .......................................................................20
Heart Rate Variability ................................................................................20
Heart Rate ..................................................................................................23
Skin Conductance Level ............................................................................23
Subjective Units of Distress Scale .............................................................23
Statistical Analyses ................................................................................................24
Heart Rate Variability ................................................................................24
Heart Rate ..................................................................................................24
Skin Conductance Level ............................................................................25
Subjective Units of Distress Scale .............................................................25
III. Results ..........................................................................................................................26
Self-report Measures ..............................................................................................26
Heart Rate ..............................................................................................................28
Skin Conductance Level ........................................................................................28
Heart Rate Variability ............................................................................................31
SDNN .........................................................................................................31
RMSSD ......................................................................................................32
SDSD .........................................................................................................32
pNN50 ........................................................................................................32
Low Frequency ..........................................................................................33
High Frequency ..........................................................................................33
Low Frequency / High Frequency Ratio ....................................................33
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IV. Discussion ....................................................................................................................37
Limitations and Conclusions..................................................................................41
Appendices .........................................................................................................................44
Appendix A: Inclusion and Exclusion criteria ...................................................................44
Appendix B: The Subjective Units of Distress Scale ........................................................46
Appendix C: The Liebowitz Social Anxiety Scale ............................................................47
References ..........................................................................................................................48

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